993 resultados para nutrient resorption rate
Resumo:
Läntisen Pien-Saimaan vesistön alueella on ilmennyt voimakasta sinileväkukintaa vuosina 2006 - 2009. Yksi tehokas keino vähentää sinilevien määrää ja parantaa vedenlaatua, onravinnepitoisuuksien alentaminen virtausohjauksen avulla. Tästä on 70 vuoden kokemus Pien- Saimaan itäosissa, joissa Vehkataipaleen pumppaamon virta on pitänyt vedenlaadun hyvänä huolimatta vesialuetta raskaasti rasittavasta puunjalostusteollisuudesta. Diplomityössä selvitetään mahdollisuuksia toteuttaa virtauksenohjausta myös läntisen Pien-Saimaan puolella, jolloin tavoitteena on vedenlaadun paraneminen. Vedenlaadun parantamista edellyttää myös Euroopan unionin vesipuitedirektiivi. Selvityksessä tarkasteltiin virtauksenohjauksen eri toteutusvaihtoehtoja ja arvioitiin näiden vaikutuksia eri alueiden vedenlaatuun. Tämän lisäksi kartoitettiin ja arvioitiin eri vaihtoehdoista aiheutuvia riskejä. Näiden tietojen pohjalta päädyttiin suositeltaviin virtauksenohjauksen toteutusvaihtoehtoihin, joita ovat Kolhonlahti – Kolinlahti välillä toteutettu pumppaus ja mahdollisen Kutilan kanavan rakentamisen yhteydessä Kopinsalmen pumppaamo. Kolhonlahti – Kolinlahti sijaitsee Pien-Saimaan koillisosassa lähellä Rehulaa. Muista tarkastelluista kohteista saatiin yhdistelemällä suositeltavaksi vaihtoehdoksi myös Vehkataipaleen pumppaamon virran kasvattaminen yhdistettynä Kirjamoinsalmen tai Kopinsalmen pumppaamoon. Tämän lisäksi eri vaihtoehdoille laadittiin alustava kustannustarkastelu. Selvityksessä käytettyjä menetelmiä ja tuloksia voidaan soveltaa myös muihin vastaavan tyyppisiin vesistöjen kunnostushankkeisiin. Työssä on lisäksi koottu yhteen yleistietoja Pien-Saimaasta ja sen tunnetuista virtauksista.
Resumo:
Intensive swine production is an important agricultural and economical activity in Europe. The high availability of pig slurry (PS) lead to attractive fertilization strategy to reduce costs, therefore is mainly applied as fertilizer in agricultural systems. The optimization N fertilization in these areas should be taken in into to avoid nitrates losses by lixiviation and to achieve maximum efficiency in crop nutrition. Many studies have shown that PS applications can achieve satisfactory yields in different crops by partially or completely replacing synthetic fertilizers. In addition, for the last years, in Northeast Spain (Catalonia) has been widely extended the double-cropping forage system.
Resumo:
This paper proposes a methodology to predict benzene uptake rate in ambient air, using passive samplers with Tenax TA. Variations in the uptake rate were found to occur as a function of the sampling time; and were greater at the beginning of sampling. An empirical model was obtained and values for uptake rate agree with literature. Concentration prediction errors can be minimized by using sampling times of 4 to 14 days, thus avoiding the influence of excessive uptake rates in the initial days and the influence of back diffusion at the end of the sampling period.
Resumo:
The underlying cause of many human autoimmune diseases is unknown, but several environmental factors are implicated in triggering the self-destructive immune reactions. Multiple Sclerosis (MS) is a chronic autoimmune disease of the central nervous system, potentially leading to persistent neurological deterioration. The cause of MS is not known, and apart from immunomodulatory treatments there is no cure. In the early phase of the disease, relapsing-remitting MS (RR-MS) is characterized by unpredictable exacerbations of the neurological symptoms called relapses, which can occur at different intervals ranging from 4 weeks to several years. Microbial infections are known to be able to trigger MS relapses, and the patients are instructed to avoid all factors that might increase the risk of infections and to properly use antibiotics as well as to take care of dental hygiene. Among those environmental factors which are known to increase susceptibility to infections, high ambient air inhalable particulate matter levels affect all people within a geographical region. During the period of interest in this thesis, the occurrence of MS relapses could be effectively reduced by injections of interferon, which has immunomodulatory and antiviral properties. In this thesis, ecological and epidemiological analyses were used to study the possible connection between MS relapse occurrence, population level viral infections and air quality factors, as well as the effects of interferon medication. Hospital archive data were collected retrospectively from 1986-2001, a period in time ranging from when interferon medication first became available until just before other disease-modifying MS therapies arrived on the market. The grouped data were studied with logistic regression and intervention analysis, and individual patient data with survival analysis. Interferons proved to be effective in the treatment of MS in this observational study, as the amount of MS exacerbations was lower during interferon use as compared to the time before interferon treatment. A statistically significant temporal relationship between MS relapses and inhalable particular matter (PM10) concentrations was found in this study, which implies that MS patients are affected by the exposure to PM10. Interferon probably protected against the effect of PM10, because a significant increase in the risk of exacerbations was only observed in MS patients without interferon medication following environmental exposure to population level specific viral infections and PM10. Apart from being antiviral, interferon could thus also attenuate the enhancement of immune reactions caused by ambient air PM10. The retrospective approach utilizing carefully constructed hospital records proved to be an economical and reliable source of MS disease information for statistical analyses.
Resumo:
Methane combustion was studied by the Westbrook and Dryer model. This well-established simplified mechanism is very useful in combustion science, for computational effort can be notably reduced. In the inversion procedure to be studied, rate constants are obtained from [CO] concentration data. However, when inherent experimental errors in chemical concentrations are considered, an ill-conditioned inverse problem must be solved for which appropriate mathematical algorithms are needed. A recurrent neural network was chosen due to its numerical stability and robustness. The proposed methodology was compared against Simplex and Levenberg-Marquardt, the most used methods for optimization problems.
Resumo:
EONIA is a market based overnight interest rate, whose role as the starting point of the yield curve makes it critical from the perspective of the implementation of European Central Bank´s common monetary policy in the euro area. The financial crisis that started in 2007 had a large impact on the determination mechanism of this interest rate, which is considered as the central bank´s operational target. This thesis examines the monetary policy implementation framework of the European Central Bank and changes made to it. Furthermore, we discuss the development of the recent turmoil in the money market. EONIA rate is modelled by means of a regression equation using variables related to liquidity conditions, refinancing need, auction results and calendar effects. Conditional volatility is captured by an EGARCH model, and autocorrelation is taken into account by employing an autoregressive structure. The results highlight how the tensions in the initial stage of the market turmoil were successfully countered by ECB´s liquidity policy. The subsequent response of EONIA to liquidity conditions under the full allotment liquidity provision procedure adopted after the demise of Lehman Brothers is also established. A clear distinction in the behavior of the interest rate between the sub-periods was evident. In the light of the results obtained, some of the challenges posed by the exit-strategy implementation will be addressed.
Resumo:
APROS (Advanced Process Simulation Environment) is a computer simulation program developed to simulate thermal hydraulic processes in nuclear and conventional power plants. Earlier research at VTT Technological Research Centre of Finland had found the current version of APROS to produce inaccurate simulation results for a certain case of loop seal clearing. The objective of this Master’s thesis is to find and implement an alternative method for calculating the rate of stratification in APROS, which was found to be the reason for the inaccuracies. Brief literature study was performed and a promising candidate for the new method was found. The new method was implemented into APROS and tested against experiments and simulations from two test facilities and the current version of APROS. Simulation results with the new version were partially conflicting; in some cases the new method was more accurate than the current version, in some the current method was better. Overall, the new method can be assessed as an improvement.
Resumo:
Published data containing fungicide concentrations that control 50% (IC50) of a given fungus were analyzed. In the analysis we considered: (i) the IC50 determined in vitroand in vivofor a given fungicide and for a specific fungus; (ii) the concentration (g/ha) of active ingredient for the fungicide indicated to control a specific disease in the field; (iii) water volume of 120/L used in the spray; (iv) the fungicide a.i. concentration (mg/L) in 120 L volume; (v) and the ratio of the concentration used in the field with that determined in the laboratory. The analysis were performed by using IC50 data for DMIs, QoIs, a carbamate and a benzimidazol against the following fungi Bipolaris sorokiniana, Drechslera tritici-repentis, D. siccans, Fusarium graminearum, Puccinia triticina, Exserohilum turcicum, Phakopsora pachyrhiziand Corynespora cassiicola. The fungicide concentrations sprayed in the field were 33.9 (D. siccansand trifloxystrobin) to 500,000.0 (E. turcicumand iprodione) times higher than that determined in the laboratory. It was concluded that the IC50 was not related to the concentration used in the field and therefore should be used to compare the power among fungicides and to monitor the fungal sensitivity shift towards fungicides
Resumo:
The interception of the rainfall by the forest canopy has great relevance to the nutrient geochemistry cycle in low fertility tropical soils under native or cultivated forests. However, little is known about the modification of the rainfall water quality and hydrological balance after interception by the canopies of eucalyptus under pure and mixed plantations with leguminous species, in Brazil. Samples of rainfall (RF), throughfall (TF) and stemflow (SF) were collected and analyzed in pure plantations of mangium (nitrogen fixing tree -NFT), guachapele (NFT) and eucalyptus (non-nitrogen fixing tree -NNFT) and in a mixed stand of guachapele and eucalyptus in Seropédica, State of Rio de Janeiro, Brazil. Nine stemflow collectors (in selected trees) and nine pluviometers were randomly disposed under each stand and three pluviometers were used to measure the incident rainfall during 5.5 months. Mangium conveyed 33.4% of the total rainfall for its stem. An estimative based on corrections for the average annual precipitation (1213 mm) indicated that the rainfall's contribution to the nutrient input (kg ha-1) was about 8.42; 0.95; 19.04; 6.74; 4.72 and 8.71 kg ha-1 of N-NH4+, P, K+, Ca+2, Mg+2 and Na+, respectively. Throughfall provided the largest contributions compared to the stemflow nutrient input. The largest inputs of N-NH4+ (15.03 kg ha-1) and K+ (179.43 kg ha-1) were observed under the guachapele crown. Large amounts of Na+ denote a high influence of the sea. Mangium was the most adapted species to water competitiveness. Comparatively to pure stand of eucalyptus, the mixed plantation intensifies the N, Ca and Mg leaching by the canopy, while the inputs of K and P were lower under these plantations.
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Gasification offers an environmentally friendly alternative for conventional combustion enabling the use of low grade and troublesome fuel such as municipal waste. While combustion converts fuel directly into thermal energy and noxious gases, gasification thermally converts fuel into gas that can be used in multiple applications. The purpose of this work is to get to know the gasification as a phenomenon and examine the kinetics of gasification. The main interest is in the reaction rates of the most important gasification reactions - water-gas, Boudouard and shift reaction. Reaction rate correlations found in the scientific articles are examined in atmospheric pressure in different temperatures.
Resumo:
Tämän diplomityön tavoitteena on tutkia ekologisen kestävyyden huomioimista Suomen innovaatiojärjestelmässä. Ekologinen kestävyys on osa laajempaa kestävän kehityksen käsitettä, joka syntyi jo 1980-luvun lopulla. Sillä viitataan toimintaan, joka jättää mahdollisuuksia tuleville sukupolville yhtä paljon tai enemmän kuin nykyään on käytettävissä. Kestävyyteen pyritään nykyisin laajalti ja sen toteutumisen turvaamiseksi on laadittu muun muassa EU-maat, Pohjoismaat ja Suomen kattavat strategiat. Ekologisen kestävyyden suurimmat uhat ovat tällä hetkellä ilmastonmuutos, biodiversiteetin pieneneminen ja ravinteiden kierto. Kestävä innovointi ja ympäristöinnovaatiot ovat tärkeitä keinoja ekologiseen kestävyyteen panostettaessa. Näissä innovaatioissa kyse on teknologian, talouden ja ympäristön tasapainosta. Suomen innovaatiotoimintaa tuetaan ja kansallista kilpailukykyä pidetään yllä kansallisen innovaatiojärjestelmän avulla. Suomen innovaatiojärjestelmässä on useita eri tason toimijoita. Tärkeimpinä voidaan pitää päättäjiä, rahoittajia ja tutkimuksen tuottajia. Rahoituksen suuntaaminen vaikuttaa siihen, mistä aihealueista tutkimusta tuotetaan. Suomen Akatemialla, Tekesillä ja Sitralla on ekologista kestävyyttä edistäviä ohjelmia. Lisäksi mm. SHOK:issa on huomioitu ekologisuus. Perustutkimusta rahoitetaan Suomen innovaatiojärjestelmässä huomattavasti soveltavaa tutkimusta vähemmän. Ekologiseen kestävyyteen panostavan tutkimuksen teemoista nousee selkeimmin esiin kestävä energiantuotanto sekä kestävä rakentaminen. Jatkotutkimuksena voisi selvittää, kuinka nämä panostukset ovat vaikuttaneet suomalaiseen rakennusalaan.